1. Field of the Invention
Toxoplasma gondii (hereinafter “T. gondii”) is an apicomplexan parasite that chronically infects approximately one-third of the world's population. Disease caused by T. gondii, called toxoplasmosis, occurs in some infected persons. For example, when a pregnant woman acquires this infection for the first time during gestation, T. gondii can be transmitted congenitally to her fetus, causing death or severe ocular impairment and brain damage in the fetus. For most such persons infects the retina and/or brain. Recrudescence of the persistent encysted bradyzoites can then cause disease lifelong. Infection in immune compromised persons also may cause severe, life threatening toxoplasmosis. This is a significant medical problem for persons with organ and stem cell transplantation, cancers, immunosuppressive medications and the acquired immunodeficiency syndrome.
The first line treatment of this disease is the combination of pyrimethamine and sulfadiazine. While highly effective against tachyzoites, these drugs may cause hematological side effects, other toxicities, and hypersensitivity. Further, no current drugs are effective in eliminating T. gondii bradyzoites in cysts. To cure T. gondii infections definitively, anti-toxoplasma medicines must cross the placenta, enter the retina, traverse the blood brain barrier as well as cyst walls and bradyzoite membranes. They also must cross the host cell membrane, the parasitophorous vacuole, and tachyzoite membranes. Improved drugs with significantly less toxicity, greater efficacy against tachyzoites and encysted bradyzoites, and access to infected tissues are urgently needed.
The general field of the invention is the production and use of pharmaceutical formulations comprised of oligonucleotide analogs, complex phosphorodiamidate morpholino olgomers, and complex phosphorodiamidate morpholino olgomers chemically coupled to specifically selected peptide sequences in order to prevent, inhibit, abrogate, mitigate, cure, or otherwise lessen the incidence or severity of disease. In one aspect, the field of the invention is the production and use of pharmaceutical formulations comprised of oligonucleotide analogs, complex phosphorodiamidate morpholino olgomers, and complex phosphorodiamidate morpholino olgomers chemically coupled to specifically selected peptide sequences in order to prevent, inhibit, abrogate, mitigate, cure, or otherwise lessen the incidence or severity of infection caused by apicomplexan parasites.
2. Description of Related Art
Antisense phosphorodiamidate morpholino olgomers (hereinafter “PMO”) have been well studied as promising tools with potential to block ribonucleic acid transcription (Summerton, J; Weller, D (1997); Antisense & Nucleic Acid Drug Development 7 (3): 187-95), and as such have potential value as therapeutics whose purpose is to control protein expression. PMO designed as antibacterial agents (U.S. Pat. No. 6,677,153 to Iversen et al) and antiviral agents (U.S. Pat. No. 6,828,105 to Stein et al) have been disclosed. The ability of PMO to pass through cellular membrane structures so as to be available to interact with RNA targets is limited (Summerton, J. E.; (2007) Curr. Top. Med. Chem.; 7, 651-660). It has been shown that certain oligopeptides, in particular cationic oligopeptides, preferably arginine-rich oligopeptides, facilitate transport across membranes (Tzan, et al., (1993); American Journal of Physiology 265, No. 6, Part 1, pp. C1637-C1647). In addition, certain bioactive molecules, such as drugs, can be transported across membranes after chemical conjugation to some cationic oligopeptides (see for example U.S. Pat. No. 7,229,961 to Rothbard et al). It was disclosed that the cellular uptake of PMO chemically joined to selected cationic peptides is enhanced relative to the PMO alone (Moulton H, et al. (2004) Bioconjugate Chem 15:290-299). PMO conjugated to peptide (hereinafter “PPMO”) having enhanced transport across cell membranes and enhanced antisense binding activity has been disclosed (U.S. Pat. No. 7,468,418 to Iversen et al). U.S. Pat. No. 8,067,571 to Weller et al disclosed PPMO with enhanced transport across cell membranes along with enhanced antibacterial activity and antisense binding activity. PPMO demonstrating enhanced transport across cell membranes along with enhanced antiviral activity and antisense binding activity was disclosed (U.S. Pat. No. 8,084,433 to Iversen et al). PMO or PPMO with oligonucleotide analog structures specifically engineered to interrupt RNA activity of apicomplexan parasites have not been reported. PMO or PPMO with oligonucleotides analog structures specifically engineered to identify, recognize, define, or validate molecular structures within or expressed by T. gondii have not been reported.
All citations are specifically incorporated by reference in their entirety for all purposes.